Modular suspension system and components thereof

ABSTRACT

An elastomeric spring suspension is described for supporting a longitudinally extending vehicle frame rail above first and second axles forming a tandem axle configuration. The suspension includes a frame hanger assembly mounted to the vehicle frame rail. The frame hanger assembly has two full spring modules, each of which includes two shear springs, a progressive spring rate load cushion having a pyramidal shape with a flattened top surface and a spring mount for mounting the springs. A saddle assembly is connected to the spring mount, and an equalizing beam is connected to the saddle assembly and further connected to the axles. The spring rate for the suspension increases almost linearly as a function of sprung load, resembling a pneumatic suspension. Accordingly, the suspension exhibits excellent ride quality, without sacrificing roll stability.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/045,069, which is entitled Elastomeric Spring VehicleSuspension and was filed on Mar. 10, 2008. This application claims thebenefit of U.S. patent application Ser. No. 12/045,069 under 35 U.S.C.§120, and incorporates U.S. patent application Ser. No. 12/045,069herein by reference.

BACKGROUND

The present invention generally relates to vehicle suspensions. Moreparticularly, the present invention relates to elastomeric springvehicle suspensions, such as for use in vocational or heavy haul truckapplications.

Single spring rate suspensions and variable spring rate suspensions foruse in vocational or heavy haul truck applications are known.

Single spring rate suspensions have a fixed spring rate that generallymust be set at a level that produces a suspension with either acomfortable ride or a stiff suspension exhibiting adequate rollstability. As a result, either roll stability or ride quality iscompromised in single spring rate suspensions, depending upon theselected spring rate.

Variable rate suspensions overcome this deficiency of single ratesuspensions by providing for multiple spring rates during operation. Asthe sprung load is increased, the spring rate is correspondinglyincreased.

An example of a variable spring rate elastomeric spring suspension foruse in vocational or heavy haul truck applications is shown in U.S. Pat.No. 6,585,286, the disclosure of which is hereby incorporated herein byreference. That suspension utilizes bolster springs and auxiliarysprings to achieve its variable spring rate.

The spring rate for such a suspension can change due to the engagementor disengagement of the auxiliary spring as a function of load. The ridequality of a lightly loaded chassis having such a suspension is quitegood without sacrificing roll stability at rated chassis load. When alightly to moderately loaded chassis with such a suspension encountersmoderate to large variations in roadway or operating conditions,frequent engagement and disengagement of the auxiliary spring may occur.For each such engagement or disengagement of the auxiliary spring, thespring rate for the system may undergo an abrupt change known asstrike-through effect. Ride quality may be compromised as a result.Graphically, the spring rate has a discontinuity, which may berepresented as a step function, at the load where the auxiliary springis engaged or disengaged.

Prior elastomeric spring suspensions for vocational or heavy haul truckapplications require their elastomeric springs to undergo loading thatis compressive, tensile and/or shearing in nature. Tensile loadingcauses elastomeric break down.

In view of the conditions identified above with respect to prior springvehicle suspensions for vocational or heavy haul truck applications, itis desired to provide a new and improved suspension for thoseapplications.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are described herein withreference to the drawings, wherein like parts are designated by likereference numerals, and wherein:

FIG. 1 is a side elevational view of a vehicle suspension constructed inaccordance with principles disclosed herein;

FIG. 2 is a side elevational view of a frame hanger assembly and asaddle assembly illustrated in FIG. 1;

FIG. 3 is an end view of the frame hanger assembly and the saddleassembly illustrated in FIG. 2;

FIG. 4 is a side elevational view of a frame hanger spring moduleillustrated in FIG. 1;

FIG. 5 is an end view of the frame hanger spring module illustrated inFIG. 4;

FIG. 6 is a side elevational view of a frame hanger illustrated in FIG.1;

FIG. 7 is a sectional view of the frame hanger illustrated in FIG. 6,taken along lines 7-7 thereof;

FIG. 8 is a perspective view of a shear spring in accordance with anexemplary embodiment;

FIG. 8A is a top view of the shear spring illustrated in FIG. 8;

FIG. 8B is a side elevational view of the shear spring illustrated inFIG. 8;

FIG. 8C is a sectional view of the shear spring illustrated in FIG. 8A,taken along lines A-A thereof;

FIG. 8D is a sectional view of the shear spring illustrated in FIG. 8A,taken along lines B-B thereof;

FIG. 9 is a perspective view of another shear spring in accordance withan exemplary embodiment;

FIG. 10 is an elevational view of a progressive spring rate load cushionillustrated in FIG. 1;

FIG. 11 is a perspective view of another embodiment of a progressivespring rate load cushion;

FIG. 12 is a side elevational view of a spring mount illustrated in FIG.1;

FIG. 13 is a sectional view of the spring mount illustrated in FIG. 12,taken along lines 13-13 thereof;

FIG. 14 is a top plan view of the spring mount illustrated in FIG. 12;

FIG. 15 is a sectional view of the spring mount illustrated in FIG. 14,taken along lines 15-15 thereof;

FIG. 16 is a side elevational view of the saddle assembly illustrated inFIG. 1;

FIG. 17 is a side elevational view of the saddle portion of the saddleassembly illustrated in FIG. 16;

FIG. 18 is a bottom plan view of the saddle illustrated in FIG. 17;

FIG. 19 is an end view of the saddle illustrated in FIG. 17;

FIG. 20 is a side elevational view of a fabricated equalizing beamillustrated in FIG. 1;

FIG. 21 is a top plan view of the fabricated equalizing beam illustratedin FIG. 20;

FIG. 22 is a side elevational view of another suspension constructed inaccordance with principles disclosed herein;

FIG. 23 is a side elevational view of still another suspensionconstructed in accordance with principles disclosed herein;

FIGS. 24A and 24B are graphical representations pertaining to theoperating characteristics of suspensions constructed in accordance withprinciples disclosed herein;

FIG. 25 is a side elevational view of an alternative frame hangerassembly for use in suspensions constructed in accordance withprinciples disclosed herein;

FIG. 26 is a side-elevational view of a frame hanger assembly inaccordance with an exemplary embodiment;

FIG. 27 is a top plan view of the frame hanger assembly illustrated inFIG. 26;

FIG. 28 is an end view of the frame hanger assembly illustrated in FIG.26;

FIG. 29 is a side elevational view of a spring housing in accordancewith an exemplary embodiment;

FIG. 30 is a top plan view of the spring housing illustrated in FIG. 29;

FIG. 31 is an end view of the spring housing illustrated in FIG. 29;

FIG. 32 is a sectional view of the spring housing illustrated in FIG.29, taken along lines A-A thereof;

FIG. 33 is a sectional view of the spring housing illustrated in FIG.31, taken along lines B-B;

FIG. 34 is a side elevational view of a load cushion in accordance withan exemplary embodiment;

FIG. 35 is a top plan view of the load cushion illustrated in FIG. 34;

FIG. 36 is an end view of the load cushion illustrated in FIG. 34;

FIG. 37 is a vertical cross section view of the load cushion illustratedin FIG. 34, taken along lines A-A thereof;

FIG. 38 is a vertical cross section view of the load cushion illustratedin FIG. 36, taken along lines B-B thereof;

FIG. 39 is a perspective view of a spring mount in accordance with anexemplary embodiment;

FIG. 40 is a top plan view of the spring mount illustrated in FIG. 39;

FIG. 41 is a bottom plan view of the spring mount illustrated in FIG.39;

FIG. 42 is an end view of the spring mount illustrated in FIG. 39;

FIG. 43 is a sectional view of the spring mount illustrated in FIG. 42,taken along lines A-A thereof;

FIG. 44 is a sectional view of the spring mount illustrated in FIG. 41,taken along lines B-B thereof;

FIG. 45 is a side elevational view of a saddle in accordance with anexemplary embodiment;

FIG. 46 is a bottom plan view of the saddle illustrated in FIG. 45;

FIG. 47 is an end view of the saddle illustrated in FIG. 45;

FIG. 48 is a perspective view of a saddle cap end portion in accordancewith an exemplary embodiment;

FIG. 49 is a side elevational view of the saddle cap end portionillustrated in FIG. 48;

FIG. 50 illustrates an exemplary base plate of the load cushionillustrated in FIG. 34;

FIG. 51 illustrates an exemplary rate plate of the load cushionillustrated in FIG. 34;

FIG. 52 illustrates a perspective view of another load cushion inaccordance with an exemplary embodiment;

FIG. 53 illustrates a perspective view of another load cushion inaccordance with an exemplary embodiment;

FIG. 54 is a graphical representation of operating characteristicsobtainable with suspensions constructed in accordance with theprinciples disclosed herein;

FIG. 55 is a side-elevational view of a frame hanger assembly inaccordance with an exemplary embodiment;

FIG. 56 is a top plan view of the frame hanger assembly illustrated inFIG. 55; and

FIG. 57 is an end view of the frame hanger assembly illustrated in FIG.55.

DETAILED DESCRIPTION OF THE INVENTION 1. Exemplary Suspension

FIGS. 1-21 illustrate embodiments of a vehicle suspension generallydesignated 50 and components thereof. The vehicle suspension 50 isdesigned to support longitudinally extending C-shaped vehicle framerails 52 above laterally extending vehicle axles (not shown) of a tandemaxle configuration for the vehicle. In an alternative embodiment, thevehicle frame rails 52 may comprise box frame rails, I-frame rails (forexample, frame rails comprising an I-beam), or some other type of framerail. As will be appreciated by those skilled in the art, components forthe vehicle suspension 50 and the other suspensions described herein areduplicated on each side of the vehicle. It will also be appreciated thatvehicle wheels (not shown) are mounted to the ends of the vehicle axlesin a known manner. Further, it will be appreciated that the vehicleframe rails 52 may be connected by one or more vehicle frame crossmembers (not shown).

Those skilled in the art will further understand that a suspension,arranged in accordance with the suspension 50 and the componentsthereof, alternatively may be attached to frame rails of a trailer (forexample, a trailer that connects to a semi-tractor). The frame rails ofa trailer may comprise frame rails such as those described above oranother type of frame rail.

For purposes of this description, unless specifically describedotherwise, hereinafter, “vehicle” refers to a vehicle or a trailer. Inthis way, for example, a vehicle frame refers to a vehicle frame or atrailer frame. Furthermore, for purposes of this description, the leftside of a vehicle refers to a side of the vehicle on an observer'sleft-hand side when the observer faces the back of the vehicle, and theright side of the vehicle refers to a side of the vehicle on anobserver's right-hand side when the observer faces the back of thevehicle. Furthermore still, for purposes of this description, “outboard”refers to a position further away from a center line, running from thefront to the back of a vehicle, relative to “inboard” which refers to aposition closer to that same center line.

The vehicle suspension 50, in accordance with a given embodiment, mayhave and/or provide, but is not limited to having and/or providing, oneor more of the following characteristics: (i) a continuously increasingspring rate (curvilinear and with no discontinuities) as a function ofan increasing load applied to the suspension 50, (ii) an almost linearlyincreasing spring rate as a function of increasing load applied to thesuspension 50, (iii) minimal interaxle brake load transfer and/orimproved articulation due to a pivot point created at a center bushing76 of an equalizing beam 78, (iv) minimal or no tensile loading to oneor more springs of the suspension 50, (v) improved durability due to areduced number of fasteners, mechanical joints that reduce thecriticality of fastener preloads, and the elimination of tensile loadingin one or more springs of the suspension 50, (vi) good ride quality on alightly loaded chassis without sacrificing roll stability at ratedchassis load, (vii) no restrictions with regards to the usage of tirechains, and (viii) no abrupt change in spring rate due to engagement ordisengagement of an auxiliary spring as the vehicle employing thesuspension 50 encounters moderate to large variations in roadway oroperating conditions.

As shown in FIG. 1, the suspension 50 includes a frame hanger assembly54 having two spring modules 56 which are mounted on the frame rail 52in a known manner. In this regard, each spring module 56 includes aframe attachment portion 58 having holes for attaching the spring moduleto an adjacent frame rail 52.

Each of the spring modules 56 includes a window-like opening 60 definedby the top wall 62, the side walls 64 and the bottom wall 66 (see, also,for example, FIGS. 6 and 7). Within each opening 60, shear springs 68are positioned between the side walls 64 and a spring mount 70 centrallypositioned within the opening. Preferably, the shear springs 68 aremounted in compression in the spring module 56. The compression loadapplied to the shear springs 68, the side walls 64, and the spring mount70 may increase as the expected maximum load rating of the vehicle isincreased. For example, for a first expected maximum load rating, theshear springs 68, the side walls 64, and/or the spring mount 70 may bemounted in compression on the order of approximately 13,000 pounds ofload. As another example, for a second expected maximum load ratingwhich is greater than the first expected maximum load rating, the shearsprings 68, the side walls 64, and/or the spring mount 70 may be mountedin compression on the order of approximately 20,000 pounds of load.

In addition, within each opening 60, a progressive spring rate loadcushion 72 is positioned between the spring mount 70 and the top wall 62of the opening 60. Preferably, the load cushion 72 has a continuouslyincreasing spring rate (during the loading of the load cushion 72), asdescribed in greater detail below.

It will be appreciated herein throughout that while the spring modules56 are described as having the shear springs 68 and the progressivespring rate load cushions 72, if the vehicle load has a sufficientlysmall magnitude in the fully loaded state, a spring module 56 havingonly the shear springs 68 (i.e., not having a progressive spring rateload cushion) may suffice. By way of example only, the sufficientlysmall magnitude of the vehicle load in the fully loaded state may be avehicle load between 0 and 8,000 pounds or between 0 and 10,000 pounds.

Two suspension saddle assemblies 74 are attached to the spring mounts 70included within each opening 60. One saddle assembly 74 is positioned onthe outboard side of spring modules 56, as shown in FIG. 3. The othersaddle assembly 74 is positioned on the opposite (inboard) side of thespring modules 56, as also shown in FIG. 3. The saddle assemblies 74 areattached to a center bushing 76 of a longitudinally extending fabricatedequalizing beam 78, also known in the art as a walking beam.

Each beam 78 includes bushing tubes or canisters 80 positioned onopposite ends thereof. Each end of beam 78 is connected to a respectiveend of the vehicle axles (not shown) in a known manner.

FIGS. 2 and 3 illustrate embodiments of frame hanger assembly 54 and thesaddle assembly 74. In this embodiment, frame hanger assembly 54includes the two spring modules 56, in which each spring module 56includes a frame hanger 82, two shear springs 68, a progressive springrate load cushion 72, and a spring mount 70. Likewise, in thisembodiment, each saddle assembly 74 includes a saddle portion 84 and asaddle cap end portion 86. The saddle portion 84 of each saddle assembly74 is connected to the spring mounts 70, which provide mounting surfacesfor shear springs 68 and progressive spring rate load cushions 72.

While installed between the spring mounts 70 and the side walls 64, theshear springs 68 are preferably held in compression between the springmounts 70 and the side walls 64, preferably under approximately 13,000to 20,000 pounds of load. In other words, the shear springs 68 do notundergo tensile loading. In this way, the fatigue life of the shearsprings 68 is increased compared to elastomer springs that are subjectedto such loading. The shear springs 68 are also oriented generallysideways, as illustrated, such that they act in shear and thereby haveimproved performance. One or both of the shear springs 68 in the springmodule 56 may be replaced with another shear spring or springs thatis/are configured like the shear springs 68.

The progressive spring rate load cushions 72 are mounted between thespring mounts 70 and the respective top walls 62 of the openings 60. Theload cushions 72 preferably have a continuously increasing spring rateduring loading. Accordingly, the suspension 50 has a continuouslyincreasing spring rate during loading. The load cushions 72 act incompression and do not undergo tensile loading, so they also haveincreased fatigue life over other springs (for example, elastomersprings) that are subjected to such loading.

FIGS. 4 and 5 illustrate an embodiment of a full frame hanger springmodule 56. In this embodiment, each full frame hanger spring module 56includes a frame hanger 82, a spring mount 70, two shear springs 68 anda progressive spring rate load cushion 72 (see FIG. 2). Each springmount 70 includes two saddle mounting bores 114 (see FIGS. 12-15) thatare positioned inboard and outboard, respectively, of the frame hanger82 to permit the saddle assembly 74 to be attached (see also FIGS. 2 and3).

The bottom wall 66 of the opening 60 constitutes a rebound stop forsuspension 50. This integrated rebound control eliminates the need forancillary devices for such purpose. A snubber 90 may be included andattached to the bottom wall 66 of the opening 60, as shown, to furtherreduce audible noise that may be generated when the suspension goes intorebound. As an example, the snubber 90 may comprise an elastomericmaterial that may be attached to the bottom wall 66 using an adhesive orother fastener(s). Examples of the elastomeric material describedhereinafter are applicable to the elastomeric material of the snubber90.

FIGS. 6 and 7 illustrate additional details of an embodiment of theframe hanger 82. In particular, FIGS. 6 and 7 illustrate that side wall64 of this embodiment includes a pocket 92. The other side wall 64preferably includes a similarly arranged pocket 92 (not shown). Pockets92 preferably have height and width dimensions optimized for locating arespective shear spring 68, and thus this embodiment eliminates the needfor fasteners to retain the shear springs 68, which may alternatively beused. The width of the frame hanger opening 60, and hence the spanbetween the pockets 92, is also preferably optimized for compression ofthe shear springs 68 in assembly. Further, the depth of pocket 92 isoptimized for clearance of the shear springs 68 in operation as theshear springs 68 move through their full stroke. Pocket depthoptimization also provides secondary vertical and horizontal retentionof the shear springs 68 in addition to the retention provided by thecompression of the shear springs 68 and by the coefficient of frictionbetween the shear springs 68 and the mating member (for example, apocket in side wall 64 or a pocket in the spring mount 70). With thepreferred dimensions, no fasteners are required to retain the shearsprings 68 in assembly, although embodiments that do require fastenersare also within the scope of the subject matter disclosed herein.

Referring again to FIG. 7, the top wall 62 for each opening 60 may useand/or comprise, for example, two elliptical shapes in perpendicularplanes to form a dome-like configuration 94 to control bulging of theprogressive spring rate load cushion 72 during loaded conditions,thereby increasing the useful life of the load cushion. Anotheradvantage of dome-like configuration 94 is that it eliminates potentialsharp edges that could damage the load cushion.

Each frame hanger 82 preferably has a symmetrical design, as shown. Thispermits each frame hanger 82 to be positioned on either the left side orthe right side of the vehicle. Each frame hanger 82 may have a framebolt pattern optimized for retaining frame hanger 82 to its associatedvehicle frame rail under all operating conditions. Optimizing the boltpattern may include, for example, minimizing the quantity of fastenersneeded to reliably tighten the frame hanger 82 to the frame rail 52and/or to maximize stretching of the fasteners.

FIGS. 8, 8A, and 8B illustrate various views of an embodiment of a shearspring 68. In this embodiment, the shear spring 68 is constructed ofload blocks 96 bonded to plates 98. In one respect, the load blocks 96(for example, elastomeric load blocks) may comprise an elastomericmaterial (i.e., an elastomer) such as natural rubber, synthetic rubber,styrene butadiene, synthetic polyisoprene, butyl rubber, nitrile rubber,ethylene propylene rubber, polyacrylic rubber, high-densitypolyethylene, thermoplastic elastomer, a thermoplastic olefin (TPO),urethane, polyurethane, a thermoplastic polyurethane (TPU), or someother type of elastomer.

In this regard and in particular, the load blocks 96 may comprise anelastomer defined as American Society of Testing and Materials (ASTM)D2000 M4AA 717 A13 B13 C12 F17 K11 Z1 Z2. In this case, Z1 representsnatural rubber and Z2 represents a durometer selected to achieve adesired shear rate. The selected durometer may be based on a givenpredefined scale, such as the Shore A scale, the ASTM D2240 type Ascale, or the ASTM D2240 type D scale. In a preferred embodiment, inaccordance with the Shore A scale, Z2, for example, is preferably 70±5.In another embodiment, in accordance with the Shore A scale, Z2 is, forexample, within the range of 50 to 80. Other examples of Z2 and rangesfor Z2 are also possible.

In another respect, the load blocks 96 (for example, viscoelastomericload blocks) may comprise a viscoelastomeric material that (i) haselastic characteristics when the shear spring 68 is under a load withina given range and when that load is removed, and (ii) has non-elasticcharacteristics (for example, does not return to an original non-loadedshape) if the applied load exceeds the greatest load of the given range.The given range may extend from no load to a maximum expected load plusa given threshold. The given threshold accounts for possible overloadingof the shear spring 68. As an example, the viscoelastomeric material maycomprise amorphous polymers, semi-crystalline polymers, and biopolymers.Other examples of the viscoelastomeric material are also possible.

In accordance with an embodiment, the load blocks 96 may also compriseone or more fillers. The filler(s) may optimize performance of the loadblocks 96. The fillers may include, but are not limited to, wax, oil,curing agents, and/or carbon black. Such fillers may optimizeperformance by improving durability of the load blocks 96 and/or tuningthe load blocks 96 for a given shear load and/or a given compressiveload applied to the load blocks 96. Improving durability of the loadblocks 96 through the use of fillers may include, for example,minimizing a temperature rise versus loading characteristic of loadblocks 96 and/or maximizing shape retention of the load blocks 96.

The shear springs 68 may be formed, for example, by inserting the plates98 into a mold (not shown). The plates 98 may each be coated with acoating material. As an example, the coating material may comprise amaterial comprising zinc and phosphate, modified with calcium. Thecoating material may have a coating weight of 200-400 milligrams persquare foot. Other examples of the coating material are also possible. Abonding agent may be applied to the coated plates for bonding the plates98 to the load blocks 96. As an example, the bonding agent may compriseChemlok® manufactured by the Lord Corporation, Cary, N.C., USA. Otherexamples of the bonding agent are also possible. Applying the coatingmaterial and/or applying the bonding agent may occur prior to, during,and/or after insertion of the plates 98 into the mold. After applyingthe coating material and the bonding agent, the load block material(while in a pourable form) may be inserted into the mold to form theload blocks 96.

In a preferred embodiment, any exposed portion of the plates 98 (forexample, a portion of the plates 98 not covered by the load blockmaterial) is protected against corrosion by a means other than the loadblock material. In other embodiments, some exposed portions of theplates 98 (e.g., the edges of the plates 98) may not be protectedagainst corrosion, whereas any other exposed portions of the plates 98are protected against corrosion. FIGS. 8C and 8D illustrate sectionalviews of an embodiment of the shear spring 68, and in particular,through-holes 99 within the plates 98. The through-holes 99 permits theload block material to flow more easily through the mold when formingthe load blocks 96.

As explained above, the shear springs 68 are mounted in compression. Inan illustrated embodiment, compression of the shear spring 68 is due tothe compressive load provided by mounting them between the springpockets (for example, pocket 92) in the side walls 64 of the springmodule 56 and pockets formed in the spring mount 70. Other means ofpreloading the shear springs may alternatively be used.

The shear springs 68 contribute to the vertical spring rate of thesuspension 50 through their shear spring rate. This vertical spring rateis constant over the entire range of motion for the suspension 50. For aspring module with elastomeric shear springs, the vertical spring ratecan be customized for any given shear spring geometry by using anelastomer with a different durometer rating.

The compressive spring rate for the shear springs 68 is preferablydesigned to be constant over a small range of compression, to aid inassembly, to be asymptotic in the as-installed condition, and to keepsuspension longitudinal travel due to shear spring compression duringvehicle acceleration or deceleration to a minimum, preferably under fivemillimeters.

Each of the plates 98 for the shear spring 68 has minimal, if any,effect on the shear spring rate thereof. The plates 98 are used foroptimization of the compressive characteristics of the shear springs 68.The compression rate of the shear spring 68 may be increased by addingan additional plate 98 with a corresponding load block 96, whereas thecompression rate of the shear spring 68 may be decreased by removal of aplate 98 and a corresponding load block 96. The plates 98 can be made ofany of a variety of suitable materials, including, but not limited to,iron, steel, aluminum, plastic, a composite material, or some othermaterial. The dimensions and shape of the plates 98 may be selected soas to obtain preferred packaging, weight and aesthetic characteristicsof the shear springs 68 and for locating the shear springs 68 in thehanger and spring mount pockets. The plates 98 may be fully, or at leastsubstantially, encapsulated in elastomer to further enhance theircorrosion resistance and friction at the mating suspension members.

In accordance with an embodiment, the desired shear rate of the shearspring 68 is approximately 403 N/mm (or approximately 2,300 pound forceper inch (i.e., lb_(f)/in)), the initial compressive spring rate of theshear spring 68 is approximately 6,000 N/mm (or approximately 34,200lb_(f)/in), the maximum shear travel of shear spring 68 is approximately68.7 mm (approximately 2.7 inches), and the installed height of shearspring 68 is approximately 83.8 mm (approximately 3.3 inches).

FIG. 9 illustrates an embodiment of a shear spring 68 having an optionaltab 100 incorporated into the periphery thereof. The tab 100 ensuresproper shear spring orientation during assembly. It will be appreciatedthat any such tabs, if used, can by any shape, size or count.

FIG. 10 illustrates an embodiment of a progressive spring rate loadcushion 72. The progressive spring rate load cushion 72 may bepositioned between the spring mount 70 and the dome-like configuration94 and attached to the spring mount 70 by fasteners. Generally, eachprogressive spring rate load cushion 72 is designed to have at least onetapered wall (for example, tapered walls 105, 107) and generallysimilarly shaped horizontal cross sections of different sizesthroughout. For these embodiments, each horizontal cross section has agenerally similar shape as other horizontal cross sections, but it doesnot have the same size or sectional area as other horizontal crosssections. The size change factor, or ratio of similitude, is a functionof the taper of the at least one tapered wall. The horizontal crosssections can be any geometric shape desired for packaging, weight oraesthetics.

In accordance with an exemplary embodiment, the load cushion 72 is anelastomeric progressive spring rate load cushion shaped to resemble apyramid. In this regard, the load cushion 72, as illustrated in FIG. 10,includes a base plate 102, an elastomer 104 shaped to resemble thepyramid, and a flattened top surface 106. The base plate 102 can be madeof a variety of suitable materials, including, but not limited to, iron,steel, aluminum, plastic, and a composite material. The base platedimensions and shape can be varied to any dimension or shape desired forpackaging, weight, and aesthetics. Preferably, the base plate 102 isdimensioned to match the top surface of the spring mount 70, to locatethe fasteners securing it to the spring mount 70, and to minimizeoverall mass.

The size and dimensions of the elastomer 104 for the progressive springrate load cushion 72 is optimized for the vertical spring raterequirements. For the present application, the vertical spring rate forthe progressive spring rate load cushion 72 continuously increases withincreasing load, defining a curvilinear shape with no discontinuities ona graph illustrating spring rate as a function of sprung load. The sizeand dimensions of the elastomer 104 may be based on a shape factor,which is a ratio of an area of a loaded surface (for example, aflattened top surface 106) to the total area of unloaded surfaces freeto expand (for example, the four walls of the elastomer 104 leading fromthe base plate 102 to the top surface 106).

A preferred progressive spring rate load cushion 72 has a shape closelyresembling a pyramid with a flattened top surface 106, as indicated.With this preferred shape, the vertical spring rate for the progressivespring rate load cushion 72 linearly increases with increasing load. Inone embodiment, the cross section of the base of the elastomer 104 is 5inches by 6 inches, the cross section of the top surface 106 is 0.8inches by 0.8 inches and the height of the elastomer 104 is 3.2 inches.The spring rate of the progressive spring rate load cushion 72 may beoptimized by varying the durometer of the elastomer 104. By varying thedurometer, a family of interchangeable progressive spring rate loadcushions can be created.

FIG. 11 illustrates an embodiment of an elastomeric progressive springrate load cushion 72 having its base plate 102 fully encapsulated in theelastomer 104 for greater corrosion resistance and to provide frictionat the spring mount interface. In an alternative embodiment, a portionof the base plate 102 may be exposed (e.g., not covered by the elastomer104). This exposed portion of the base plate 102 may be protectedagainst corrosion by a means other than the elastomer 104. In yetanother embodiment, all of the exposed portion of the base plate 102,except for the edges of the exposed portion of the base plate 102 may beprotected against corrosion by a means other than the elastomer 104. Byway of example, the base plate 102 may extend between 0.25 inches to 0.5inches beyond all portions of the widest portion of the pyramidalportion of the elastomer 104.

As illustrated in FIG. 11, the load cushion 72 has ears 108 incorporatedinto the base plate 102. Each ear 108 includes a through-hole 109through which a fastener may be inserted and fastened to the springmount 70 and/or to the saddle assembly 74 so as to retain the loadcushion 72 within the suspension 50. The through-hole 109 may be any ofa variety of shapes. For example, the through-hole 109 may berectangular. In this way, the inserted fastener may comprise a roundhead and square neck bolt, known in the art as a carriage bolt. Asanother example, the through-hole 109 may be circular. In this way, theinserted fastener may comprise a hex head bolt. Other suitablefasteners, and correspondingly shaped through-holes, may alternativelybe used.

FIGS. 12-15 illustrate an embodiment of the spring mount 70 includedwithin each spring module 56. The spring mount 70 includes a generallyflat top surface 110 upon which progressive spring rate load cushion 72is seated, a pair of pockets 112 positioned on opposite sides thereoffor accommodating the shear springs 68, and a pair of saddle mountingbores 114 positioned on opposite sides thereof forming saddle interfacesand permitting attachment to the suspension saddles 84.

The oppositely positioned pockets 112 are preferably dimensioned forlocating the shear springs 68 in assembly. The horizontal spanseparating the pockets 112, provided by the dimensions of the springmount 70, is also optimized for desired compression of the shear springs68 in assembly. In addition, the depth of the pockets 112 may beoptimized for clearance of the shear springs in operation as the shearsprings move through their full stroke. Pocket depth optimization alsoprovides secondary vertical and horizontal retention of the shearsprings in addition to the retention provided by the compression of theshear springs and by the coefficient of friction between the shearsprings and the mating member, With the preferred dimensions, nofasteners are required to retain the shear springs 68 in assembly,although embodiments that do require fasteners to retain the shearsprings 68 are also within the scope of the subject matter disclosedherein.

The saddle interface for spring mount 70 forms a female portion 116 of aspring mount-saddle mechanical joint having a desired angle formaintaining joint integrity in all operating conditions. For a saddleassembly in a suspension that is operable to handle a first maximumload, the desired angle is preferably about 160 degrees. In analternative arrangement, such as a saddle assembly in a suspension thatis operable to handle a second maximum load, where the second maximumload is greater than the first maximum load, the desired angle may beless than 160 degrees, such as 140 degrees. A person having ordinaryskill in the art will understand that the desired angle of the femaleportion of the spring mount-saddle mechanical joint may be a number ofdegrees between 120 degrees and 180 degrees.

The spring mount-saddle interface mechanical joint eliminates directshear loading of the fasteners 117 (see FIG. 2), since the shear loadingis borne exclusively by the joint. The spring mount-saddle interfacemechanical joint reduces the criticality of fastener preload andminimizes the number of fasteners required. The fasteners 117 may eachcomprise a carriage bolt, a standard hex head bolt or a hex flange bolt,or some other type of fastener.

A spring mount fillet 300 is preferably included at the apex of thesaddle interface for the spring mount 70 to minimize stressconcentrations. The spring mount fillet 300 may have a radius of twentymillimeters. The spring mount fillet 300 prevents intimate contact atthe peak of the saddle interface for the spring mount 70 when the saddle84 is fastened thereto. The fillet 300 also ensures that the only activesurfaces for the mechanical joint are the inclined planes of the joint.In this way, required tolerances are eased and as-cast surfaces may beused to construct the joint.

The spring mount 70 may be made from any of a variety of materials. In apreferred embodiment, the spring mount 70 is made from D55 ductile iron.In another embodiment, the spring mount 70 may, for example, be madefrom another type iron, steel, aluminum, a composite material, such ascarbon fiber, or some other material.

FIGS. 16-19 illustrate an embodiment of a saddle assembly 74 includedwithin a suspension. The saddle assembly 74 includes a saddle portion(or more simply, a saddle) 84 and a saddle cap end portion 86. One halfbore 119 a is formed in the center hub interface of saddle portion 84 toform an upper half of a saddle cap arrangement, and another half bore119 b is formed in the saddle cap end portion 86 to form a lower half ofthe saddle cap arrangement. Due to relaxed tolerances for this saddlecap arrangement, the saddle assembly 74, including the saddle portion 84and the saddle cap end portion 86, may be assembled as cast. Thisconstruction provides for a saddle cap interface with the attachedequalizing beam or other vehicle component and is known in the art.Saddle cap bores 118 may be machined into the saddle portion 84 and thesaddle cap end portion 86 so that fasteners 120 shown in the form ofstuds and nuts (see FIG. 16) may secure the saddle portion 84 and thesaddle cap end portion 86 together when the saddle assembly 74 isattached to an equalizing beam 78 or other component.

FIGS. 45-49 illustrate another embodiment that may be used within thesaddle assembly 74. In particular, FIGS. 45-47 illustrate a saddle 84Aand FIGS. 48 and 49 illustrate a saddle cap end portion 86A. The saddle84A and the saddle cap end portion 86A may be made of iron, steel,aluminum, a composite material, or some other material, and may eachcomprise a separate cast that is formed from a casting process known tothose having ordinary skill in the art. In this way, the saddle 84A mayinclude through-holes 84B that are formed when the saddle 84A is cast,and the saddle cap end portion 86A may include through-holes 86B thatare formed when the saddle cap end portion 86A is cast. Fasteners, suchas the fasteners 117, may be inserted into the through-holes 84B, 86Bfor subsequent fastening and attachment of the saddle cap end portion86A to the saddle 84A. In an alternative embodiment, the through-holes84B and/or the through-holes 86B may be formed by machining.

The saddles 84, 84A preferably have a space frame/truss-like geometry orconstruction, as illustrated, to minimize component stress duringsuspension operating conditions and to minimize component mass. Thesaddles 84, 84A further have spring mount mounting bores 122 foralignment with the saddle mounting bores 114 of the spring mount 70 orthe spring mount 346 (see FIG. 26). The saddles 84, 84A include a maleportion 124 for the preferred spring mount interface thereof, designedto be received within the counterpart female portion 116 of the springmount-saddle interface mechanical joint. For a saddle assembly for usein a suspension to handle the first maximum load, a span 138 of the maleportion 124 of the mechanical joint is also preferably 160 degrees. Inan alternative arrangement, such as the saddle assembly in a suspensionthat is operable to handle the second maximum load, the span 138 of themale portion of the mechanical joint may be less than 160 degrees, suchas 140 degrees. A person having ordinary skill in the art willunderstand that the span 138 may be a number of degrees between 120degrees and 180 degrees.

A saddle round 302 is preferably included at the apex of the springmount interface for the saddles 84, 84A to minimize stressconcentrations. The saddle round 302 may be larger than the spring mountfillet 300. In a preferred case, the saddle round 302 has a radius thatis ten millimeters larger then the radius of the spring mount fillet300. In this way, if the spring mount fillet 300 has a radius of twentymillimeters, then the saddle round 302 has a radius of thirtymillimeters. The saddle round 302 prevents intimate contact at the peakof the spring mount interface for the saddles 84, 84A when the springmount 70 or the spring mount 346 is fastened thereto. The saddle round302 also ensures that the only active surfaces for the mechanical jointare the inclined planes of the joint. In this way, required tolerancesare eased and as-cast surfaces for the saddle and the spring mount maybe used to construct the joint.

FIGS. 20 and 21 illustrate an embodiment of an equalizing beam 78 (alsoreferred to as a walking beam) that may be used in the suspension 50, aswell as in the other suspensions described herein. The equalizing beam78 is preferably a fabricated component having a top plate 126, a bottomplate 128, side plates 130, two end bushing hubs 80, and one centerbushing hub 132. Center bushing hub 132 is included in a central portionof the side plates 130 to retain a center bushing 134 mounted thereinfor connection to the saddle assembly 74. Additional bushings 136 areretained in the end bushing hubs 80 for connection to the tandem axles(not shown) in a known manner.

The use of the equalizing beam 78 results in minimal interaxle brakeload transfer due to a real pivot point created at the equalizing beamcenter bushing 134. The use of the equalizing beam 78 also improvesarticulation by virtue of this real pivot point.

The suspensions described herein are modular. As one example, thevehicle ride height may be set, as desired. In particular, the vehicleride height may be changed by changing the frame hanger to another witha different dimension between the frame attachment holes and the shearspring pockets. The vehicle ride height may also be changed by changingthe saddle to another with a different dimension between the center hubinterface and the spring mount interfaces thereof. In addition,replacement of both the frame hanger and saddle with others havingdifferent dimensions may change the vehicle ride height.

The principles described herein may also be used in a variety ofelastomeric spring suspensions for a variety of axle configurations. Forexample, while an elastomeric spring suspension for a tandem axlechassis having an equalizing beam has been described, the principlesextend to single axle chassis, to tandem axle chassis without equalizingbeams, and to tridem axle chassis (with or without equalizing beams), byexchanging the saddle for another with the appropriate axle interface.

It is to be noted that the load capacity for the suspension may beincreased to match chassis size by the addition of spring modules orpartial spring modules to the frame hanger assembly, or by replacementof the progressive spring rate load cushion with another, such as a loadcushion having a flattened top surface (apex) with a larger surface areaand/or a larger base. Alternatively, load capacity for the suspensionmay be reduced to match chassis size by removal of spring modules orpartial spring modules from the frame hanger assembly, or by replacementof the progressive spring rate load cushion with another, such as a loadcushion having a flattened top surface (apex) with a smaller surfacearea and/or a smaller base.

2. Additional Exemplary Suspensions

FIG. 22 illustrates another spring suspension 200 embodiment designedpreferably for use with a vocational or heavy haul truck having a tandemaxle configuration. Three full spring modules 56 define the frame hangerassembly 202. In addition, the saddle assemblies 204 used in suspension200 have three spring mount interfaces. Outside of the foregoing, thesuspension 200 is similar to the suspension 50 illustrated in FIG. 1.The use of the additional spring module 56 generates greater loadcapacity for the suspension 200 than for the suspension 50 illustratedin FIG. 1, assuming everything else is identical.

The spring suspension 200, in accordance with a given embodiment, mayhave and/or provide, but is not limited to having and/or providing, oneor more of the following characteristics: (i) a continuously increasingspring rate (curvilinear and with no discontinuities) as a function ofan increasing load applied to the suspension 200, (ii) an almostlinearly increasing spring rate as a function of increasing load appliedto the suspension 200, (iii) minimal interaxle brake load transferand/or improved articulation due to a pivot point created at a centerbushing of the equalizing beam 78, (iv) minimal or no tensile loading toone or more springs of the suspension 200, (v) improved durability dueto a reduced number of fasteners, mechanical joints that reduce thecriticality of fastener preloads, and the elimination of tensile loadingin one or more springs of the suspension 200, (vi) good ride quality ona lightly loaded chassis without sacrificing roll stability at ratedchassis load, (vii) no restrictions with regards to the usage of tirechains, and (viii) no abrupt change in spring rate due to engagement ordisengagement of an auxiliary spring as the vehicle employing thesuspension 200 encounters moderate to large variations in roadway oroperating conditions.

FIG. 23 illustrates yet another embodiment of a spring suspension 250designed preferably for use with a vocational or heavy haul truck havinga tandem axle configuration. The suspension 250 has two full springmodules 56 and one half/partial spring module 252 defining a framehanger assembly 254. The two full spring modules 56 are constructedgenerally as described above for the embodiments of the suspensions 50and 200, illustrated in FIGS. 1 and 22 respectively.

In the embodiment of FIG. 23, the partial spring module 252 includes aframe attachment portion 255 having a bottom wall 256. The progressivespring rate load cushion 72 is retained by fasteners and positionedbetween the bottom wall 256 and the spring mount 70 included as part ofthe partial spring module 252. The bottom wall 256 may include adome-like configuration, such as the dome-like configuration 94described above. The saddle assemblies 204 used in the suspension 250may be similar to those used in the suspension 200 illustrated in FIG.22. The use of a partial spring module 252, in addition to the two fullspring modules 56, generates greater load capacity for the suspension250 than the suspension 50 illustrated in FIG. 1, assuming everythingelse is identical.

The spring suspension 250, in accordance with a given embodiment, mayhave and/or provide, but is not limited to having and/or providing, oneor more of the following characteristics: (i) a continuously increasingspring rate (curvilinear and with no discontinuities) as a function ofan increasing load applied to the suspension 250, (ii) an almostlinearly increasing spring rate as a function of increasing load appliedto the suspension 250, (iii) minimal interaxle brake load transferand/or improved articulation due to a pivot point created at a centerbushing of the equalizing beam 78, (iv) minimal or no tensile loading toone or more springs of the suspension 250, (v) improved durability dueto a reduced number of fasteners, mechanical joints that reduce thecriticality of fastener preloads, and the elimination of tensile loadingin one or more springs of the suspension 250, (vi) good ride quality ona lightly loaded chassis without sacrificing roll stability at ratedchassis load, (vii) no restrictions with regards to the usage of tirechains, and (viii) no abrupt change in spring rate due to engagement ordisengagement of an auxiliary spring as the vehicle employing thesuspension 250 encounters moderate to large variations in roadway oroperating conditions.

FIG. 25 illustrates an embodiment of a frame hanger assembly 300including a frame interface (for example, attachment brackets) 302 andremovably attachable spring modules (for example, suspension attachment)304. The frame interface 302 includes a lower wall 306 permittingattachment to an upper wall 308 of each spring module 304 through theuse of fasteners 310. The fasteners 310 may be configured as thefasteners 117 (described above). The spring modules 304 may include theshear springs 68, the spring mount 70, and the progressive spring rateload cushion 72, such as those described above.

For this embodiment, the use of frame hanger assembly 300 enhances themodularity of the exemplary suspension systems. For example, thereplacement of spring modules 304 with other spring modules 304 havingsprings with a different vertical spring rate for the suspension isfacilitated. In addition, multiple vehicle frame configurations (i.e.,ride heights and frame widths) can be absorbed through modifications tothe hole/bore positions machined through the frame interface 302,permitting production of a uniform, universal spring module 304. Thisresults in reduced inventories of parts. This also permits compatibilityto any industry standard frame configuration worldwide, while alsosimplifying assembly.

The modular frame hanger assembly 300 may also be universal in the sensethat it can be sized and adapted for all vehicle frame configurations.As a result, a single spring module 304 can be used for all vehicleframe configurations. Various frame interfaces 302 may be used for eachparticularly different vehicle frame configuration.

Next, FIGS. 26-28 illustrate various views of a frame hanger assembly330 in accordance with another exemplary embodiment. The frame hangerassembly 330 may support longitudinally extending frame rails (forexample, the frame rails 52) above laterally extending vehicle axles ofa tandem axle configuration for the vehicle. As illustrated in FIG. 26,the frame hanger assembly 330 includes a frame hanger 332, springmodules 334, 335, and a saddle assembly 337 that is attached to anoutboard side of the spring modules 334, 335. FIG. 27 is a top view ofthe frame hanger assembly 330. FIG. 28 illustrates the saddle assembly337, as well as a saddle assembly 339 that is attached to an inboardside of the spring modules 334, 335. The frame hanger 332 may beattached to the spring modules 334, 335 through the use of fasteners309. The saddle assemblies 337, 339 may be attached to the springmodules 334, 335 through the use of fasteners 351. The fasteners 309,351 may be configured as the fasteners 117 (described above).

The frame hanger 332 may be arranged in various configurations forattachment to a variety of vehicles. The various vehicles may each havea respective frame configuration (for example, ride height, frame railwidth, and/or frame rail hole-pattern). In a first configuration, theframe hanger 332 may, for example, comprise a vertical wall 338 having(i) a first wall height, and (ii) a first frame hanger hole-pattern. Ina second configuration, the frame hanger 332 may, for example, comprisea vertical wall 338 having (i) a second wall height, and (ii) the firstframe hanger hole-pattern or another frame hanger hole-pattern. Forpurposes of this description, the second wall height is greater than thefirst wall height. In this way, a ride height of a vehicle may beincreased by replacing the frame hanger 332 having a vertical wall 338that has the first wall height with the frame hanger 332 having avertical wall 338 that has the second wall height and/or by replacingsaddle assemblies 337, 339 with saddle assemblies having dimensionsdifferent from those of saddle assemblies 337, 339. Other configurationsof the frame hanger 332, such as configurations that are arranged with awall height and frame hanger hole-pattern that differ from the wallheight and frame hanger hole-pattern combination of each other framehanger configuration, are also possible.

The various frame hanger hole-patterns may match up to a respectiveframe rail hole-pattern in an outboard vertical wall of a frame rail.Fasteners, such as the fasteners 117, may be inserted through the holesof the vertical wall 338 and through the outboard vertical wall of theframe rail for subsequent fastening of the frame hanger 332 to the framerail.

The frame hanger 332 may be made of iron, steel, aluminum, a compositematerial, or some other material. As illustrated in FIG. 26, the framehanger 332 includes a lower wall 336 having a first lower wall end 340and a second lower wall end 342. As illustrated in FIG. 27, the lowerwall 336 includes two sets of through-holes 311. Each set ofthrough-holes 311 is arranged in a given spring module attachmenthole-pattern that matches holes in the spring modules 334, 335. Theframe hanger 332 also includes a vertical wall 338 that extends from thewall end 340 to the wall end 342.

The spring modules 334, 335 each comprise a spring housing 344, a springmount 346, a progressive spring rate load cushion 348, and shear springs350, 352. The spring modules 334, 335 may be interchangeable, and may besymmetrical such that the spring modules 334, 335 may be positioned oneither the left side or the right side of a vehicle and on either afront or rear of the frame hanger 330. The saddle assemblies 337, 339may be attached to the spring mounts 346 and to a center bushing of alongitudinally extending fabricated equalizing beam (i.e., a walkingbeam) (not shown). Thereafter, the saddle assemblies 337, 339 may beunattached from the spring mounts 346 and/or the equalizing beam for anyof a variety of reasons (for example, servicing and/or replacement ofthe saddle assemblies 337, 339).

FIGS. 55-57 illustrate additional views of the frame hanger assembly 330in accordance with an embodiment in which the frame hanger 332 (seeFIGS. 26-28) is replaced with frame hanger 333. The frame hanger 333 maybe attached to the spring modules 334, 335 through the use of thefasteners 309.

The frame hanger 333 may be arranged in various configurations forattachment to a variety of vehicles. The various vehicles may each havea respective frame configuration (for example, ride height, frame railwidth, and/or frame rail hole-pattern). In a first configuration, theframe hanger 333 may, for example, comprise a vertical wall 341 having(i) a first wall height, and (ii) a first frame hanger hole-pattern. Ina second configuration, the frame hanger 333 may, for example, comprisea vertical wall 341 having (i) a second wall height, and (ii) the firstframe hanger hole-pattern or another frame hanger hole-pattern. Forpurposes of this description, the second wall height is greater than thefirst wall height. In this way, a ride height of a vehicle may beincreased by replacing the frame hanger 333 having a vertical wall 341that has the first wall height with the frame hanger 333 having avertical wall 341 that has the second wall height. Other configurationsof the frame hanger 333, such as configurations that are arranged with awall height and frame hanger hole-pattern that differ from the wallheight and frame hanger hole-pattern combination of each other framehanger configuration, are also possible.

The various frame hanger hole-patterns may match up to a respectiveframe rail hole-pattern in an outboard vertical wall of a frame rail.Fasteners, such as the fasteners 117, may be inserted through the holesof the vertical wall 341 and through the outboard vertical wall of theframe rail for subsequent fastening of the frame hanger 333 to the framerail.

The frame hanger 333 may be made of iron, steel, aluminum, a compositematerial, or some other material. As illustrated in FIG. 55, the framehanger 333 includes a lower wall 382 having a first lower wall end 380and a second lower wall end 381. As illustrated in FIG. 27, the lowerwall 382 includes two sets of through-holes 383. Each set ofthrough-holes 383 is arranged in a given spring module attachmenthole-pattern. The lower wall 382 may also include holes 384 forattaching the frame hanger 333 to an underside of a vehicle frame rail(for example, frame rail 52). The vertical wall 341 extends from thewall end 380 to the wall end 381.

Next, FIGS. 29-31 illustrate various views of an embodiment of thespring housing 344. The spring housing 344 may be made of iron, steel,aluminum, a composite material, or some other material. In a preferredembodiment, the spring housing 344 is preferably a casting made via acasting process known to those of ordinary skill in the art. In analternative embodiment, the spring housing 344 may be a fabrication ofmultiple castings and/or forgings. As illustrated in FIGS. 30 and 33,the spring housing 344 includes depressions 357, which are metal saversto reduce the weight of the spring housing 344.

The spring housing 344 includes an interior portion 345 in which thespring mount 346, the load cushion 348, and the shear springs 350, 352may be installed. The interior portion 345 may be defined, in part, by abottom wall 354, a top wall 356, and side walls 358, 360. The top wall356 preferably has through-holes 370 arranged in the same hole-patternas the pattern of the through-holes in the frame hanger 332 or 333, (forexample, through-holes 311 or 383). The top wall 356 may also havethrough-holes 371 that match up to through-holes on the bottom side of aframe rail and/or a frame rail lower gusset. The fasteners 309 may beinserted through the through-holes 311 or 383 and the through-holes 370so as to allow fastening and attaching of the spring modules 334, 335 tothe frame hanger. In an alternative arrangement, instead of thethrough-holes 370, the spring housing 344 may use threaded holes that donot extend all the way through the top wall 356.

FIGS. 32 and 33 are sectional views of the spring housing 344. Asillustrated in these figures, the spring housing 344 includes the springhousing pockets 364, 366, and a dome-like configuration 368 in the topwall 356. The dome-like configuration 368 may control bulging of theload cushion 348 when the load cushion 348 is under a load, so as toincrease the useful life of the load cushion 348. The dome-likeconfiguration 368 also eliminates sharp edges that could damage the loadcushion 348 when the load cushion 348 contacts the top wall 356.

The pocket 364 has height, width, and depth dimensions preferablyoptimized for locating the shear spring 350, and the pocket 366 hasheight, width, and depth dimensions preferably optimized for locatingthe shear spring 352. A span 372 between the pockets 364, 366 ispreferably optimized for compression of the shear springs 350, 352 inassembly. The compression of the shear springs 350, 352 may, forexample, be on the order of 13,000 to 20,000 pounds of load. Further,the depth of the pockets 364, 366 is preferably optimized for clearanceof the shear springs 350, 352 in operation as the springs move throughtheir full stroke. Pocket depth optimization also provides secondaryvertical and horizontal retention of the shear springs 350, 352 inaddition to the retention provided by compression of the shear springs350, 352 and by the coefficient of friction between the shear springs350, 352 and the mating member (for example, the pockets 364, 366 andthe spring mount 346). Using the preferred dimensions, no fasteners arerequired to retain the shear springs 350, 352 in assembly, althoughalternative embodiments that require and/or use fasteners to retain theshear springs 350, 352 are also within the scope of the subject matterdisclosed herein.

In FIGS. 26 and 29, the spring housing 344 is illustrated without asnubber. However, in alternative embodiment, the spring housing 344 mayinclude a snubber above the bottom wall 354. Such a snubber may bearranged as the snubber 90 described above.

Next, FIGS. 34-38 illustrate various views of an embodiment of theprogressive spring rate load cushion 348. As illustrated in FIG. 37, theload cushion 348 includes a base plate 400, a rate plate 402, andcushion material 404 including a first cushion portion 406 and a secondcushion portion 408. The base plate 400 includes a top side 410, abottom side 412, and multiple edges 414 between the top side 410 and thebottom side 412. Similarly, the rate plate 402 includes a top side 416,a bottom side 418, and multiple edges 420 between the top side 416 andthe bottom side 418.

FIGS. 50 and 51 illustrate a plan view of embodiments of the base plate400 and the rate plate 402, respectively. As illustrated in FIGS. 50 and51, the base plate 400 and the rate plate 402 each have through-holes422 to allow the cushion material 404 to pass through the plates 400,402 during manufacture of the load cushion 348. The base plate 400includes ears 424 having through-holes 426 for mounting the load cushion348 to the spring mount 346. In a preferred embodiment, the ears 424 areoffset on opposite sides of a center line of the base plate 400. Inalternative embodiment, a center line of the ears 424 may be the same asa center line of the base plate 400. Fasteners 362 may be insertedthrough the ears 424 and fastened to the spring mount 346 and/or thesaddle assemblies 337, 339 so as to retain the load cushion 348 withinthe spring housing 344.

The base plate 400 and the rate plate 402 may be made of any of avariety of materials, such as steel, aluminum, iron, plastic, acomposite material, or some other material. In accordance with anexemplary embodiment, the edges 414, 420 each have a height of 6.35 mm(approximately 0.25 inches), the base plate 400 has a length of 152.4 mm(6.0 inches) and a width of 152.4 mm, and the rate plate 402 has alength of 152.4 mm and width of 152.4 mm. The exemplary length and widthdimensions of the base plate 400 do not account for the dimensions ofthe ears 424. A person having ordinary skill in the art will understandthat the plates 400, 402 may have dimensions other than those listedabove.

FIG. 38 is a vertical cross section view of the load cushion illustratedin FIG. 36, taken along lines B-B thereof. As illustrated in FIG. 38,the cushion portion 406 has a top surface 428 that is flat. Inaccordance with an exemplary embodiment, each vertical cross section ofthe cushion portion 406 has two tapering edges, such as tapering edges430, 432 illustrated in FIG. 38. Additionally, the cushion portion 406has similarly shaped horizontal cross sections of different sizesthroughout. In particular, each horizontal cross section has a generallysimilar shape as other horizontal cross sections, but it does not havethe same size or sectional area as the other horizontal cross sections.The size change factor (for example, a ratio of similitude) for thehorizontal cross section is a function of taper. The largest horizontalcross section of the cushion portion 406 is preferably bonded to the topside 416 of the rate plate 402, whereas the smallest cross section ofthe cushion portion 406 is preferably the top surface 428. Thehorizontal cross sections of the cushion portion 406 can be anygeometric shape (for example, circular, rectangular, or triangular)desired for packaging, weight, or aesthetics. FIGS. 52 and 53 illustratealternative embodiments of a load cushion having a base plate 400, arate plate 402, and cushion material 404 including the cushion portions406, 408.

The size and dimensions of the cushion portion 406 may be based on theshape factor described above. In accordance with an embodiment in whichthe cushion portion 406 has a pyramidal shape and by way of example, thelargest horizontal cross section of the cushion portion 406 has a lengthof 155.4 mm (approximately 6.1 inches) and width of 155.4 mm, thesmallest cross section of the cushion portion 406 has a length of 45.7mm (approximately 1.8 inches), and the height of the cushion portion 406is 83 mm (approximately 3.3 inches). A person having ordinary skill inthe art will understand that the cushion portion 406 may alternativelyhave other dimensions.

The cushion portion 408 preferably has horizontal cross sections havinga shape similar to the shape of horizontal cross section shape of therate plate 402. These horizontal cross sections of the cushion portion408 may have dimensions that are substantially similar to the dimensionsof the rate plate 402. In this case, substantially similar is plus orminus 15 percent. In accordance with an exemplary embodiment in whichthe rate plate 402 has a rectangular shape (with or without roundedcorners), the largest horizontal cross section(s) of the cushion portion408 may have a length of 155.4 mm and a width of 155.4 mm, whereas thesmallest horizontal cross section(s) of the cushion portion 408 may havea length of 145.4 mm (approximately 5.7 inches) and a width of 145.4 mm.

In this embodiment, the cushion material 404 may comprise any of avariety of materials. In one respect, the cushion material 404 maycomprise an elastomer such as natural rubber, synthetic rubber, styrenebutadiene, synthetic polyisoprene, butyl rubber, nitrile rubber,ethylene propylene rubber, polyacrylic rubber, high-densitypolyethylene, thermoplastic elastomer, a thermoplastic olefin (TPO),urethane, polyurethane, a thermoplastic polyurethane (TPU), or someother type of elastomer. In this regard and in particular, the cushionmaterial 404 may comprise an elastomer defined as ASTM D2000 M4AA 621A13 B13 C12 F17 K11 Z1, wherein Z1 represents a durometer selected toachieve a desired compressive rate curve. The selected durometer may bebased on a given predefined scale, such as the Shore A scale, the ASTMD2240 type A scale, or the ASTM D2240 type D scale. In a preferredembodiment, in accordance with the Shore A scale, Z1, for example, ispreferably 70±5. In another embodiment, in accordance with the Shore Ascale, Z1 is, for example, within the range of 50 to 80. Other examplesof Z1 are also possible.

In another respect, the cushion material 404 may comprise aviscoelastomeric material that has elastomeric characteristics when theload cushion 348 is under a load within a range of no load to a maximumexpected load to be applied to the load cushion plus a given threshold.The given threshold accounts for possible overloading of the loadcushion 348. As an example, the viscoelastomeric material may compriseamorphous polymers, semi-crystalline polymers, and biopolymers.

The load cushion 348 may be formed by inserting the base plate 400 andthe rate plate 402 into a mold (not shown). The base plate 400 and therate plate 402 may be coated with a coating material (an example, ofwhich is described above). A bonding agent may be applied to the coatedplates for bonding the plates to the cushion material 404. Applying thecoating material and/or applying the bonding agent may occur prior to,during, and/or after insertion of the plates 400, 402 into the mold.After application of the coating material and the bonding agent, thecushion material 404 may be inserted into the mold. The cushion material404 preferably covers the edges 414, 420 or at least a substantialportion of the edges 414, 420. As an example, the substantial portion ofthe edges 414, 420 may include all portions of the edges 414, 420 exceptfor chaplet portions which are used to position the plates 400, 402within the mold. The cushion material 404 at the edges 414, 420 may be1.5 mm (approximately 0.06 inches) thick.

Those having ordinary skill in the art will understand that the loadcushions used in the suspensions 50, 200, 250, 300 may be arranged asthe load cushion 348. Those having ordinary skill in the art will alsounderstand that the load cushion 348 could be arranged with one or moreadditional rate plates similar to the rate plate 402 and, for eachadditional rate plate, a respective cushion portion similar to thecushion portion 408. In such alternative arrangements, each additionalrate plate is inserted into the mold prior to the cushion material 404.

Next, FIGS. 39-44 illustrate various views of an embodiment of thespring mount 346. The spring mount 346 includes sides 452, 454. Thespring mount 346 may be symmetrical such that the sides 452, 454 may beused on either the inboard or the outboard side of a vehicle. The springmounts 70 used in the suspensions 50, 200, 250, 300 may be arranged asthe spring mount 346.

The spring mount 346 includes a generally flat top surface 464 uponwhich a load cushion (for example, the load cushion 348) is seated, andwall portions 466, 468. Having the flat top surface 464 at a level lowerthan a top portion of the wall portions 466, 468 allows for use of ataller load cushion. In an alternative arrangement, the top surface 464may be at the same level as the wall portions 466, 468.

As illustrated in FIG. 43, the spring mount 346 includes a pair ofpockets 470, 472 positioned on opposite sides of the spring mount 346.The pockets 470, 472 are preferably dimensioned for locating the shearsprings 350, 352 in assembly. A horizontal span 471 that separates thepockets 470, 472 is optimized for desired compression of the shearsprings 350, 352 in assembly. A depth of the pockets 470, 472 may beoptimized for clearance of the shear springs 350, 352 in operation asthe shear springs 350, 352 move through their full stroke. Pocket depthoptimization also provides secondary vertical and horizontal retentionof the shear springs 350, 352 in addition to the retention provided bythe compression of the shear springs 350, 352 and by the coefficient offriction between the shear spring 350 and the mating members (forexample, the pockets 364, 470) and the coefficient of friction betweenthe shear spring 352 and the mating members (for example, the pockets366, 472). With the preferred dimensions of span 471, the depth ofpockets 470, 472, the span 372, the depths of pockets 364, 366 and alength of the shear springs 350, 352, no fasteners are required toretain the shear springs 350, 352 in assembly, although embodiments thatdo require fasteners to retain shear springs 350, 352 are also withinthe scope of the subject matter disclosed herein.

As illustrated in FIGS. 39 and 40, the spring mount 346 includes: (i) anoutboard saddle interface 456 that forms a female portion of amechanical joint having a given angle, (ii) an inboard saddle interface458 that forms a female portion of another mechanical joint having thegiven angle, (iii) an outboard saddle mounting bore 460, (iv) an inboardsaddle mounting bore 461, and (iv) load cushion mounting bores 462. Thesaddle mounting bores 460, 461 are part of the saddle interfaces 456,458, respectively. Fasteners inserted into mounting bores of the saddles337, 339 and the saddle mounting bores 460, 461 allow for attachment ofthe saddles 337, 339 to the spring mount 346.

FIG. 44 illustrates a female portion 482 of a spring mount-saddlemechanical joint having a desired angle for maintaining joint integrityin all operating conditions. As an example, for a saddle assembly in asuspension that is operable to handle a first maximum load, the desiredangle is preferably about 160 degrees. As another example, for a saddleassembly in a suspension that is operable to handle a second maximumload, the second maximum load being greater than the first maximum load,the desired angle may be less than 160 degrees (for example, 140degrees). The spring mount-saddle interface mechanical joints eliminatedirect shear loading of the fasteners 351 (see FIG. 26), since the shearloading is borne exclusively by the joints. The spring mount-saddleinterface mechanical joints reduce the criticality of fastener preloadand minimize the number of fasteners required. A person having ordinaryskill in the art will understand that desired angle may be a number ofdegrees between 120 degrees and 180 degrees.

An apex of the saddle interfaces 456, 458 may include a spring mountfillet 480 so as to minimize stress concentrations. In accordance withan exemplary embodiment, the fillet 480 has a radius of twentymillimeters. The fillet 480 prevents intimate contact at the peak of thesaddle interfaces 456, 458 when the saddles 337, 339, respectively, arefastened thereto. The fillets 480 ensure that the only active surfacesfor the mechanical joints are the inclined planes of the joints. In thisway, the required tolerances are eased and as-cast surfaces may be usedto construct the joint.

Next, in an alternative arrangement, the spring modules 334, 335 may beattached to a frame rail of a vehicle through the use of u-bolts, suchas u-bolts having two threaded ends. The frame hanger 332 or 333 is notneeded for the alternative arrangement. As an example, two u-bolts, withtheir threaded ends extending in a downward direction, may be placedover the top side of a frame rail, and then inserted through themounting holes 370 at both ends of the spring housing 344. Nuts may beinstalled on the threaded ends of the u-bolts to keep the spring housing344 in contact with the frame rail, The spring housing 335 may beattached to the frame rail in a similar manner.

Furthermore, in an alternative arrangement especially for use with avocational or heavy haul truck having a tandem axle configuration, theframe hangers 332 and/or 333 may be made to allow for attaching threespring modules (for example, three spring modules configured as thespring module 334, or two spring modules configured as spring module 334and one spring module configured as partial spring module 252). For thisalternative arrangement, saddle assemblies that are removably attachableto a respective spring mount in each of the three spring modules may beprovided. For example, the use of three spring modules provides a way togenerate greater load capacity for a vehicle suspension as compared tothe suspension 330 (see FIG. 26), assuming everything else is identical.

3. Exemplary Operating Characteristics

FIG. 24A illustrates a graphical representation of operatingcharacteristics that may be obtained for certain embodiments of thesuspensions of the type illustrated in FIGS. 1, 22 and 23, respectively.FIG. 24A illustrates suspension sprung load as a function of verticaldeflection. As shown, this function is initially generally linearincreasing progressively until the amount of vertical deflection beginsto taper off as load increases.

FIG. 24B illustrates a graphical representation of other operatingcharacteristics that may be obtained for certain embodiments of thesuspensions of the type illustrated in FIGS. 1, 22 and 23, respectively.FIG. 24B illustrates suspension spring rate as a function of suspensionsprung load. As shown, the suspensions have a continuously increasingspring rate (curvilinear and with no discontinuities) as a function ofload. Moreover, due to the preferred pyramidal shape of the progressivespring rate load cushions 72 used in these suspensions, the spring rateincreases almost linearly with increasing load. There are no abruptchanges in the vertical spring rate, as is the case with elastomericspring suspensions utilizing auxiliary springs. These operationalcharacteristics resemble the operational characteristics exhibited bypneumatic suspensions, not mechanical suspensions of this type.Accordingly, these suspensions exhibit excellent roll stability withoutcompromising ride quality.

FIG. 54 illustrates a graphical representation of similar operatingcharacteristics that may be obtained for embodiments employing thesuspensions described herein. In this regard, employing the suspensionsrefers to employing the described suspension on both the left side andright side of the vehicle. FIG. 54 illustrates suspension sprung load asa function of vertical deflection. As shown, this function is initiallygenerally linear increasingly progressively until the amount of verticaldeflection begins to taper off as load increases. Line 54A is for anembodiment employing the suspension 50 illustrated in FIG. 1.

Lines 54B, 54C, and 54D are for an embodiment employing a suspensionincluding the frame hanger assembly 330. For lines 54B, 54C, and 54D,the load cushion 348 includes the rate plate 402, and the durometer ofthe cushion material 404 is 70. For line 54B, a 0.5 inch shim plate (ormultiple shim plates equaling 0.5 inches) is inserted between the loadcushion 348 and the spring mount 346. For line 54C, a 0.25 inch shimplate (or multiple shim plates equaling 0.25 inches) is inserted betweenthe load cushion 348 and the spring mount 346. For line 54D, no shimplates are inserted between the load cushion 348 and the spring mount346.

Lines 54E, 54F, and 54G are for an embodiment employing a suspensionincluding the frame hanger assembly 330. For lines 54E, 54F, and 54G,the load cushion used within the frame hanger assembly 330 does notinclude a rate plate, but the height of the load cushion is the same asthe load cushion 348 used in the embodiment for lines 54B, 54C, and 54D.In this regard, the frame hanger assembly may be used with the loadcushion 72. The durometer of the load cushion material for lines 54E,54F, and 54G is 65. For line 54E, a 0.5 inch shim plate (or multipleshim plates equaling 0.5 inches) is inserted between the load cushionand the spring mount. For line 54F, a 0.25 inch shim plate (or multipleshim plates equaling 0.25 inches) is inserted between the load cushionand the spring mount. For line 54G, no shim plate(s) is/are insertedbetween the load cushion and the spring mount.

The suspension spring rate as a function of suspension sprung load maybe customized to achieve a desired ride quality. For instance, for eachof the suspension embodiments of the systems illustrated in FIGS. 1, 22,23, and 26, a shim plate or multiple shim plates may be inserted betweenthe mount and the load cushions 72, 348. The shim plates raise anoperating height of the load cushions 72, 348 such that loading of loadcushions 72, 348 begins for a lighter load as compared to loading of theload cushions when the shim plates are not used. In a preferredarrangement, the shim plate(s) are the same shape and size as a baseplate used within the load cushions 72, 348. In this way, the fastenersused to attach the load cushions 72, 348 or perhaps longer fasteners maybe used to secure the shim plate(s) between a mount and a load cushion.

Additionally, a given suspension employing frame hangers 300 or 330, inaccordance with a given embodiment, may have and/or provide, but is notlimited to having and/or providing, one or more of the followingcharacteristics: (i) a continuously increasing spring rate (curvilinearand with no discontinuities) as a function of an increasing load appliedto the given suspension, (ii) an almost linearly increasing spring rateas a function of increasing load applied to the given suspension, (iii)minimal interaxle brake load transfer and/or improved articulation dueto a pivot point created at a center bushing of an equalizing beamindirectly attached to the frame hangers 300 or 330, (iv) minimal or notensile loading to one or more springs of the given suspension, (v)improved durability due to a reduced number of fasteners, mechanicaljoints that reduce the criticality of fastener preloads, and theelimination of tensile loading in one or more springs of the givensuspension, (vi) good ride quality on a lightly loaded chassis withoutsacrificing roll stability at rated chassis load, (vii) no restrictionswith regards to the usage of tire chains, and (viii) no abrupt change inspring rate due to engagement or disengagement of an auxiliary spring asthe vehicle employing the given suspension encounters moderate to largevariations in roadway or operating conditions.

4. Examples of Additional Embodiments

The following clauses, enumerated within parenthesis, describeadditional embodiments.

(1) A load cushion for a suspension system, the load cushion comprising:

a cushion portion comprising a given material; and

a base plate having a top side, a bottom side, and multiple edges,

wherein the cushion portion extends away from the top side of the baseplate and has at least one vertical cross section having two taperingedges.

(2) The load cushion of clause (1), wherein the given material comprisesan elastomeric material.

(3) The load cushion of clause (1), wherein the given material comprisesa viscoelastomeric material.

(4) The load cushion of clause (1), wherein the given material comprisesa material selected from the group consisting of: (i) urethane, and (ii)polyurethane.

(5) The load cushion of clause (1), (2), (3) or (4), wherein the cushionportion is bonded to the base plate.

(6) The load cushion of clause (1), (2), (3), (4) or (5), wherein thecushion portion is pyramidal in shape and has a top surface that isparallel to the top side of the base plate.

(7) The load cushion of clause (1), (2), (3), (4), (5) or (6),

wherein portions of the top side, portions of the bottom side, andportions of the multiple edges are used as chaplets to retain the baseplate during manufacture of the load cushion, and

wherein the given material covers all of the base plate except forchaplets.

(8) The load cushion of clause (1), (2), (3), (4), (5), (6), or (7),

wherein the load cushion comprises a plurality of horizontal crosssections, and

wherein each horizontal cross section has a common shape and arespective size.

(9) The load cushion of clause (1), (2), (3), (4), (5), (6), (7) or (8),wherein the common shape is rectangular.

(10) The load cushion of clause (1), (2), (3), (4), (5), (6), (7) or(8), wherein the common shape is circular.

(11) A load cushion for a suspension system, the load cushioncomprising:

a first cushion portion;

a second cushion portion;

a base plate having a top side and a bottom side; and

a rate plate having a top side and a bottom side,

wherein the top side of the base plate is parallel to the top side ofthe rate plate,

wherein the first cushion portion extends away from the top side of therate plate and has at least one vertical cross section having twotapering edges, and

wherein the second cushion portion is located between the base plate andthe bottom side of the rate plate.

(12) The load cushion of clause (11),

wherein the base plate has multiple edges between the top side of thebase plate and the bottom side of the base plate,

wherein the rate plate has multiple edges between the top side of therate plate and the bottom side of the rate plate,

wherein the second cushion portion covers the multiple edges of baseplate, the bottom side of the base plate, and the multiple edges of therate plate, and

wherein the second cushion portion contacts the first cushion portion.

(13) The load cushion of clause (11) or (12),

wherein the base plate comprises at least one ear having a respectivemounting hole, and

wherein the load cushion is attachable to a spring mount via arespective fastener that is inserted through the hole of each ear andinto a respective hole in the spring mount.

(14) The load cushion of clause (11), (12), or (13),

wherein the base plate is bonded to the second cushion portion, and

wherein the rate plate is bonded to the first cushion portion and to thesecond cushion portion.

(15) The load cushion of clause (11), (12), (13), or (14),

wherein the base plate is made from a material selected from the groupconsisting of: (i) iron, (ii) steel, (iii) aluminum, (iv) plastic, and(v) a composite material, and

wherein the rate plate is made from a material selected from the groupconsisting of: (i) iron, (ii) steel, (iii) aluminum, (iv) plastic, and(v) a composite material.

(16) The load cushion of clause (11), (12), (13), (14), or (15), whereinthe first cushion portion and the second cushion portion areelastomeric.

(17) The load cushion of clause (11), (12), (13), (14), (15), or (16),wherein the first cushion portion and the second cushion portion areformed by an elastomer put into a mold that holds the base plate and therate plate.

(18) The load cushion of clause (11), (12), (13), (14), or (15), whereinthe first cushion portion and the second cushion portion made from amaterial selected from the group consisting of (i) a viscoelastomericmaterial, (ii) urethane, and (iii) polyurethane.

(19) The load cushion of clause (11), (12), (13), (14), (15), (16),(17), or (18), wherein the first cushion portion has a generallypyramidal shape with a flattened top surface.

(20) The load cushion of clause (11), (12), (13), (14), (15), (16),(17), (18) or (19),

wherein the load cushion comprises a plurality of horizontal crosssections, and

wherein each horizontal cross section has a common shape and arespective size.

(21) The load cushion of clause (20), wherein the common shape isrectangular.

(22) The load cushion of clause (20), wherein the common shape isrectangular.

(23) A suspension assembly comprising:

a spring housing having a first interior wall and a second interiorwall;

a first shear spring;

a second shear spring; and

a spring mount;

wherein the first shear spring is held in compression between the firstinterior wall and the spring mount and the second shear spring is heldin compression between the second interior wall and the spring mount.

(24) The suspension assembly of clause (23),

wherein the first shear spring includes a first end and a second end,

wherein the second shear spring includes a first end and a second end,

wherein the spring mount includes a first mount pocket and a secondmount pocket,

wherein the first interior wall includes a first wall pocket,

wherein the second interior wall includes a second wall pocket,

wherein the first end of the first shear spring is locatable within thefirst wall pocket,

wherein the second end of the first shear spring is locatable within thefirst mount pocket,

wherein the first end of the second shear spring is locatable within thesecond wall pocket, and

wherein the second end of the second shear spring is locatable withinthe second mount pocket.

(25) The suspension assembly of clause (23) or (24),

wherein the suspension assembly comprises a plurality of through-holes,and

wherein the suspension assembly attaches to a frame rail via a pluralityof u-bolts placed over the frame rail and through the plurality ofthrough-holes.

(26) The suspension assembly of clause (23), (24), or (25), furthercomprising:

a frame hanger comprising a lower wall and a side wall,

wherein the lower wall includes a plurality of through-holes arranged ina given pattern,

wherein the spring housing includes a plurality of holes arranged in thegiven pattern,

wherein the frame hanger is attached to the spring housing via fastenersinserted into the through-holes of the lower wall and into the holes ofthe spring housing, and

wherein the spring housing is attachable to a frame rail via fastenersinserted into through-holes of the side wall and into through-holes inframe rail.

(27) The suspension assembly of clause (26), further comprising:

another spring housing that is attached to the frame hanger,

wherein the other spring housing comprises another first interior wall,another second interior wall, another spring mount, another first shearspring, and another second shear spring,

wherein the other first shear spring is held in compression between theother first interior wall and the other spring mount, and

wherein the other second shear spring is held in compression between theother second interior wall and the other spring mount.

(28) The suspension assembly of clause (23), (24), (25), (26), or (27),further comprising:

a load cushion mounted to the spring mount.

(29) The suspension assembly of clause (28), wherein the load cushioncomprises an elastomeric progressive spring rate load cushion.

(30) The suspension assembly of clause (28), wherein the load cushioncomprises an elastomeric portion that has a pyramidal shape with aflattened top surface.

(31) The suspension assembly of clause (30),

wherein the spring housing further includes a top wall with a dome-likeconfiguration, and

wherein the flattened top surface contacts the dome-like configurationwhile a load is applied to the load cushion.

(32) The suspension assembly of clause (23), (24), (25), (26), (27),(28), (29), (30), or (31), further comprising:

a first saddle assembly; and

a second saddle assembly,

wherein the spring mount comprises a first saddle interface and a secondsaddle interface,

wherein the first saddle assembly attaches to the spring mount at thefirst saddle interface, and

wherein the second saddle assembly attaches to the spring mount at thesecond saddle interface.

(33) The suspension assembly of clause (32),

wherein the first saddle interface includes a female portion of a firstmechanical joint having a given angle,

wherein the second saddle interface forms a female portion of a secondmechanical joint having the given angle,

wherein the first saddle assembly includes a male portion of the firstmechanical joint having the given angle, and

wherein the second saddle assembly includes a male portion of the secondmechanical joint having the given angle.

(34) The suspension assembly of clause (33), wherein the given angle isbetween 120 degrees and 180 degrees.

(35) The suspension assembly of clause (32), further comprising:

an equalizing beam that is attached to (i) the first saddle assembly,(ii) the second saddle assembly, (iii) a first axle, and (iv) a secondaxle.

(36) A modular suspension system comprising:

a first suspension assembly as recited in clause (23); and

a second suspension assembly as recited in clause (23).

(37) The modular suspension system of clause (23), (24), (25), (26),(27), (28), (29), (30), or (31) further comprising:

a first saddle assembly; and

a second saddle assembly;

wherein the first saddle assembly is attached to a first location on aspring mount of the first suspension assembly and to a first location ona spring mount of the second suspension assembly, and

wherein the second saddle assembly is attached to a second location onthe spring mount of the first suspension assembly and to a secondlocation on the spring mount of the second suspension assembly.

(38) The modular suspension system of clause (37), further comprising:

a first equalizing beam that is attached to the first saddle assemblyand to the second saddle assembly,

wherein the first equalizing beam is attachable to a first axle and to asecond axle.

(39) The modular suspension system of clause (38), further comprising:

a third suspension assembly as recited in clause (23);

a fourth suspension assembly as recited in clause (23);

a third saddle assembly;

a fourth saddle assembly; and

a second equalizing beam that is attached to the third saddle assemblyand to the fourth saddle assembly;

wherein the third saddle assembly is attached to a first location on aspring mount of the third suspension assembly and to a first location ona spring mount of the fourth suspension assembly,

wherein the fourth saddle assembly is attached to a second location onthe spring mount of the third suspension assembly and to a secondlocation on the spring mount of the fourth suspension assembly, and

wherein the second equalizing beam is attachable to the first axle andto the second axle.

(40) The modular suspension system of clause (37), (38), or (39),further comprising:

a first load cushion mounted on the spring mount of the first suspensionassembly; and

a second load cushion mounted on the spring mount of the secondsuspension assembly.

(41) The modular suspension system of clause (40),

wherein the first load cushion comprises a first elastomeric cushion;and

wherein the second load cushion comprises a second elastomeric loadcushion.

(42) The modular suspension system of clause (41),

wherein the first elastomeric load cushion has a progressive spring rateduring loading of the first elastomeric load cushion, and

wherein the second elastomeric load cushion has a progressive springrate during loading of the second elastomeric load cushion.

(43) The modular suspension system of clause (40),

wherein the first load cushion comprises a first viscoelastomericcushion; and

wherein the second load cushion comprises a second viscoelastomeric loadcushion.

(44) The modular suspension system of clause (43),

wherein the first viscoelastomeric load cushion has a progressive springrate during loading of the first viscoelastomeric load cushion, and

wherein the second viscoelastomeric load cushion has a progressivespring rate during loading of the second viscoelastomeric load cushion.

5. Conclusion

While this invention has been described with reference to certainillustrative aspects, it will be understood that this description shallnot be construed in a limiting sense. Rather, various changes andmodifications can be made to the illustrative embodiments withoutdeparting from the true spirit and scope of the invention, as defined bythe following claims. Furthermore, it will be appreciated that any suchchanges and modifications will be recognized by those skilled in the artas an equivalent to one or more elements of the following claims, andshall be covered by such claims to the fullest extent permitted by law.

Finally, the word “exemplary” is used herein to mean “serving as anexample, instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments.

We claim:
 1. A load cushion for a suspension system, the load cushioncomprising: a cushion portion comprised of a given material; and a basehaving a top side, a bottom side, and multiple edges, wherein thecushion portion extends away from the top side of the base and has atleast one vertical cross section having two continuously inwardlytapering edges extending from the base, and wherein the load cushion isa progressive rate load cushion having a continuously increasing springrate as a load applied to the load cushion is increased.
 2. The loadcushion of claim 1, wherein the given material comprises an elastomericmaterial.
 3. The load cushion of claim 1, wherein the given materialcomprises a viscoelastomeric material.
 4. The load cushion of claim 1,wherein the given material comprises a material selected from the groupconsisting of: (i) urethane, and (ii) polyurethane.
 5. The load cushionof claim 1, wherein the base comprises a plate and the cushion portionis bonded to the plate.
 6. The load cushion of claim 1, wherein thecushion portion is pyramidal in shape and has a top surface that isparallel to the top side of the base.
 7. The load cushion of claim 1,wherein portions of the top side, portions of the bottom side, andportions of the multiple edges are used as chaplets to retain a platewithin the base during a molding operation forming the load cushion, andwherein the given material covers all of the plate except for chaplets.8. The load cushion of claim 1, further including a first ear having afirst through-hole outwardly extending from a first edge of the base,and a second ear having a second through-hole outwardly extending from asecond edge of the base.
 9. The load cushion of claim 8, wherein thefirst edge is positioned on an opposite side of the base from the secondedge.
 10. The load cushion of claim 9, wherein the first ear ispositioned 180 degrees from the second ear.
 11. The load cushion ofclaim 1, wherein the at least two continuously inwardly tapering edgesextend to a top surface of the cushion portion of the load cushion. 12.The load cushion of claim 1, including four continuously inwardlytapering walls extending from the base.
 13. The load cushion of claim12, wherein the four continuously inwardly tapering walls extend to atop surface of the cushion portion of the load cushion.
 14. A loadcushion for a suspension system, the load cushion comprising: a cushionportion comprised of a given material; and a base having a top side, abottom side, and multiple edges, wherein the cushion portion extendsaway from the top side of the base and has at least one vertical crosssection having two continuously inwardly tapering edges extending fromthe base; and wherein the load cushion is a progressive rate loadcushion having a continuously increasing spring rate as a load that isapplied perpendicular to the base of the load cushion is increased. 15.The load cushion of claim 14 wherein the at least two continuouslyinwardly tapering edges extend to a top surface of the cushion portionof the load cushion.
 16. The load cushion of claim 14, including fourcontinuously inwardly tapering walls extending from the base.
 17. Theload cushion of claim 16, wherein the four continuously inwardlytapering walls extend to a top surface of the cushion portion of theload cushion.